Jointed delivery equipment for fluids, particularly low temperature liquids

ABSTRACT

A tower-boom system for transfer of fluids in which the conduit means is relieved from bearing weight.

United States Patent Frohlich et al.

[451 July 11, 1972 [54] JOINTED DELIVERY EQUIPMENT FOR FLUIDS,PARTICULARLY LOW TEMPERATURE LIQUIDS inventors: Josef Frohllch,Dusseldorf-Rath, Germany;

Jacob Leguyt, Dordrecht, Netherlands Assignee: ManneslnannAkflengeselbchafl, Dusseldorf, Germany Filed: Oct. 12, I970 Appl. Nor:79,992

Foreign Application Priority Data Jan. I3, 1970 Germany ..P 2002 147.0Oct. I5, 1969 Germany ..P 19 53 108.9

U.S. CL... ..,.,.....................,..l37/6l5, [41/378, 248/49 Int. Cl.3671! 5/00 Field of Search 1 37/615, 276; 248/49, 292;

[56] References Cited UNITED STATES PATENTS 3,096,797 7/1963 Bily I37/61 5 2,368,994 2/1945 McGarry I 3 7/2 76 3,085,593 4/1963 Sorensen3,554,231 I/197l Caregnato l37/6l5 FOREIGN PATENTS OR APPLICATIONS1,289,223 5/1961 France l 37/6l5 Primary Examiner-M. Cary NelsonAssistant Examiner-William H, Wright AttorneySmyth, Roston & Pavitt [57]ABSTRACT A tower-boom system for transfer of fluids in which the conduitmeans is relieved from bearing weight.

12 Chins, 13 Drawing Figures PATENTEUJUL 11 m2 3. 675. 680

saw u or 5 JOIN'I'ED DELIVERY EQUIPMENT FOR FLUIDS, PARTICULARLY LOWTEMPERATURE LIQUIDS The present invention relates to crane like deliveryequipment using jointed conduits for transfer of material which can bepumped, i.e. fluids. Particularly the invention relates to improvementof equipment for loading and/or unloading tankers and which is connectedto a stationary pipeline. The equip ment includes ascending standingpiping connected to the pipeline and merging in a pivotable overhungpipe; an end pipe is suspended from the overhung pipe and carrying atits lower end means for connection to filling and drain structure.Furthermore, the equipment improved in accordance with the invention hasweight balancing means on the overhung boom structure.

Delivery equipment of the type outlined above serves for connecting theinlet-outlet studs of a tanker to a stationary pipeline. The equipmentserves for adapting the delivery and fluid transfer to difierent vesselsize, to the depth of immersion and particularly to the change thereofduring loading or unloading; also the tides differ and vary over aparticular range. The position of the end of the suspended descending orend pipe must be particularly controlled to obtain proper opera tion inspite of variation in these parameters. The parameters determineessentially the lengths of ascending and of descending pipes and of theoverhung boom pipe.

Equipment of this type is disclosed in German printed applications Nos.l,l82,l50 and l,431,658 and in British Pat. No. 918,575. These knowndevices are constructed so that the boom as a heavy load rests directlyon the ascending stand pipe. The load is particular effective directlyon the joint of stand pipe and boom pipe. The latter pipe is alsodirectly subjected to bending, and the same holds true for thesuspended, descending pipe. Different positions of the boom system varythe bending stress. Nevertheless, these loads on the several parts thatserve as conduit requires them to be rated much stronger than necessaryfor the usual pressure in the piping.

It is an object of the present invention to provide jointed constructionfor such conduit system that is particularly suited for transfer of lowtemperature liquids such as liquified natural gas, having temperature ofl80 C. The known equipment proved unsuitable for this purpose; there areseveral reasons for their failing.

First of all, all parts that come in direct contact with such a liquidhave to be made from very high quality steel to survive physical andchemical attacks by the liquid on the pipes. Also, due to the weightloads as acting on the pipes, i.e., the weight of the boom system, anddue to additional forces, such as wind pressure, the pipes must haverather thick walls which makes them considerably heavier and moreexpensive than necessary in case only flow rate and fluid pressure werethe determining factors for rating the pipes.

Sealing of the pivot or turning joints is another problem, as there areonly few materials available which do provide sealing and aresufficiently resilient at 80 C. Joints subjected to bending areparticularly critical as bending tends to misalign the axes of the jointpipes resulting in a nonuniform sealing gap which, in turn, isdifl'lcult to seal tight.

Experience has shown that during operation an ice layer forms on thepipes through which liquified natural gas is pumped, the ice layergrowing to 3 cm or even 5 cm thickness. The ice layer may impede or eveninhibit pivoting of the pipes and adds to the weight.

Large scale delivery equipment as is used today requires hydraulicactuators for pivoting and turning of parts that have to be moved. TheBritish Pat. No. 9| 8,575, shows such actuators welded to the ascending,stand pipe. Generally speaking, most known equipment has the hydraulicactuators supported somewhere on the pipes. Thus, they are heatconductively connected to the cold medium and are cooled accordingly. Onone hand, the actuators have to transmit considerable forces (to movethe heavy parts), on the other hand, the temperatures may drop belowvalues for which the hydraulic becomes inoperative.

In order to avoid these problems and deficiencies outlined above, it issuggested in accordance with the preferred embodiment of the inventionto provide a balanced boom system having a cantilever boom pivotallysupported by and extending from a tower, whereby a support arm extendsdown from and is pivotally suspended from the unsupported end of theboom. A pipe runs up in the tower, another pipe is supported in multiplelocations in the boom, and a third pipe is individually supported inplural locations in the suspended support am, the pipes are conductivelyinterconnected, e.g., through turning joints. The invention calls forseparation of fluid conduction and of the support structure for theconduits and weight balancing. This way, the weight bearing andbalancing boom system is constructed in a manner and from materialsrequiring only consideration as to statics, while the conduit system canbe optimized as to physical and chemical properties of the fluid,considering further pressure and rate of flow. The conduit system willbear only insignificant loads.

It is another feature of the invention to provide respectively coaxialrelation as between stationary turning and pivot axes of the boom systemon the one hand, and of the stationary turning and pivot axes of thepipe system on the other hand. The conduit system for the fluid issuspended in the tower and the supporting boom system, the suspensionbeing particularly provided in the intersection of the vertical turningaxis and of the horizontal pivot axis for the boom.

in addition, consideration has to be given to the extreme differences intemperatures ranging from about +50 C. to 200 C, resultingcorrespondingly in considerable changes in length of the pipes. Thus,the stand pipe that runs through the tower is suspended at its upper endfrom the top of the tower. A pipe length compensator is providedunderneath this suspension, taking up changes in length of the standpipe that are due to changes in temperature. The tower is biparted, theupper part permitting turning on the lower part, for turning of the boomsystem on a vertical axis. Horizontal twisting of the boom system isavoided as a turning joint is provided in the stand pipe underneath itssuspension from the tower.

In accordance with another feature of the invention, the boom isconstructed from two essentially parallely running beam or girdersystems. The free ends of the beam or girder systems are interconnectedby a pendulum that is a rigid extension of the suspended arm. A pivotlink, frame or the like, is linked to the lower beam system at thehorizontal pivot axis of the boom system, that is defined on the lowersystem. The pivot link structure is also pivotable connected to theupper beam system. Upper and lower beam system, pendulum support for thesuspended arm and pivot link defines a parallelogram that can vary itsangles and provides parallel motion upon up and down pivoting on thesaid horizontal pivot axis. The upper beam system is extended rearwardlyand is a bending carrier arm for the counter or balancing weight at itsfree end. The boom pipe runs in the lower beam or girder system but issuspended from the upper girder system by swinging, pendulum typestructure, disposed particularly in between the end joints of that boompipe. This structure has the advantage that a single balancing weightcan balance the boom, as will become apparent from the detaileddescription of the drawmg.

In case of cold fluids, changes in pipe length are to be considered;boom pipe and the end pipe supported in the arm that is suspended fromthe free end of the boom may become shorter, while the boom and supportarm retain their length as they are not cooled. Pivotability of thesystem must be maintained. For this, conduit and support structure areinterconnected in the linkage of boom and suspended arm so that thepivot axis of the arm is coaxial with the pivot axis of the suspendedarm. Conduit length compensators must be included in boom and end pipe.However, such compensators are not needed if the boom pipe (except forits stationary turning joint) is displaceably disposed in the boom,displacement to correspond to the change in length resulting from, forexample, extremely low temperatures. Furthermore, pivot anns pivotallylink to the respective ends of both, suspended arm and end pipe, forinterconnecting them. The two pivots of the pivot arms, together withthe upper turning joint for the end pipe and the upper pivot of thesuspended arm for a pivot quadrilateral, of which one side is variablein length. That side is given by the turning joint end and boom pipesand by the pivot of linking the suspended arm to the lower boom girder.

The several means for suspending the conduit system is the supportsystem could establish heat transfer path, cooling the supportstructure. In accordance with another feature of the invention, thesuspending and connecting elements as between tower and boom on one handand the respective pipes on the other hand, are at least partiallyconstructed from material of low thermal conductivity. The several pipesare clad in heat insulating material in order to avoid formation of icelayers thereon adding to the weight. It was found that the structureremained substantially ice free, the insulation adding significantlyless weight than the ice would.

Delivery equipment can be constructed in accordance with the principlesof the invention for loading difierent chemically etc. agressivematerial. For loading of liquified natural gas large quantities per unittime are to be pumped through the system, so that loading and unloadingof the tanker takes as little time as possible. However, in case ofvarious particular agressive materials, each loading or unloading stepinvolves usually relatively small quantities for sequentially loadingsmall tankers or tanker trucks. Also, parallel pumping of differentmaterials to different storage tanks on the cargo vessel may benecessary, acid in one, lye in the other. Accordingly, plural pipes areprovided for the stand pipe system, for the boom piping and for the endpipe system. If there are at least two parallely running pipe systems inthe equipment, at least two different fluids can be loaded and/orunloaded simultaneously Thus, there is a common boom system which isquite economical.

The plural parallel pipes are disposed side by side in common plane inthe boom and also in the suspended arm. Also, the stand pipes have theirrespective upper ends joint with the respective ends of the boom pipes.The stand pipes hang from the top of the tower by means of swingingsuspension. Hoses are connected to the lower end of the stand pipes asthey may swing out of a stationary plane upon turning. Such hoses willoffset the resulting change in length.

The construction features outlined above permit employment of turningjoints in or near the connection between stand pipe and boom pipe, andbetween the latter and the. end pipe. The hoses mentioned above may notbe usable as occasionally fluids are pumped for which suitable hoses arenot available. Thus, the hoses may better be replaced by pipe sectionswith turning joints, to offset changes in dimensions upon turning of theboom.

In case of plural parallel pipes, the individual pipes should bereleasably anchored in the equipment to permit individual replacement.For example, duplicate pipes may not be needed any longer, or a pipingmade from different material has to be used. In case piping is taken outor added, the balance conditions change. Thus, the balancing weightshould be made variable. Also, the length of the leverage for the weightis to be changed.

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter which is regarded as theinvention, it is believed that the invention, the objects and featuresof the invention and further objects, features and advantages thereofwill be better understood from the following description takeninconnection with the accompanying drawings in which:

FIG. 1 illustrates an overall side view of a delivery crane inaccordance with the preferred embodiment of the present invention;

FIG. 2 is a top elevation of FIG. 1',

FIG. 3 is a section view from plane A-A in FIG. I;

FIG. 4 shows detail F of FIG. 1, on an enlarged scale;

FIGS. 5, 6 and 7 respectively are section views from planes D-D, C-C,E--E in FIG. 1-,

FIG. 8 shows the fluid transfer section as between boom pipe and endpipe, the latter pivoted up into the horizontal;

FIG. 9 is a section view in plane BB of FIG. I, but on an enlargedscale;

FIG. I0 is a side view of a plural pipe delivery crane;

FIG. II is a top view of FIG. I], however, without bending beam;

FIG. [2 is a section view from plane B'B' in FIG. l0; and

FIG. I3 shows a modification of FIGS. 9 through I2, particularly as totransition between stand pipes and boom pipes.

Proceeding to the detailed description of the drawings, FIG. 1illustrates a delivery crane that has piping to be connected. with oneend of a stationary, onshore pipeline (not shown) by means of an elbowbend 6 (detail F of FIG. 4 as identified by circle F in FIG. I). Thedelivery crane serves to support and establish a conduit path 5. Theconduit means of the delivery equipment, and defining that path 5,includes the ascending or stand pipe 1, a pipe 2 or a boom (also calledboom pipe 2) and a descending end pipe 3. Means 4 are provided at thelower end of pipe 3 for connection to the inlet-outlet facilities of atanker.

A guide pin 7 is provided on bend 6 and slides in a guide duct 8 invertical direction. Duct 8 is anchored to foundation 9. These latterelements are provided for positioning stand pipe 1 in the horizontalpermitting expansion and contraction of pipe 1 due to temperaturechanges. A turning joint I0 connects bend 6 to pipe I. An example forsuch turning joint is shown, for example, in copending application, Ser.No. 75,9I2, filed on Sept. 28, I970.

As the joint 10 or its sealing elements may have to be removed from timeto time, pin 7 can be lowered into duct 8 to the extent necessary forsuch removal. Maintenance is thus considerably facilitated.

Pipe I is actually suspended from support tower structure I3. Moreover,the tower is the basic support for all of the other equipment of thecrane. Support tower 13 as a lower, stationary part and an upper partthat can turn on a vertical axis, there being a slewing track ring I4interposed. Pipe I is suspended from the upper, turning part of support13. (Details of the suspension are shown in FIG. 5).

Bearing pins 30 are mounted to stand pipe I near the upper end thereof.Pins 30 are received in bearing sockets 31 on tower I3. Not only dothese sockets carry the weight of stand pipe 1, but they transmit alsoturning motion of the upper part of tower 13, on a vertical axis, uponpipe 1. The turning motion is produced by a hydraulic servo motor (notshown), and is transmitted via sockets 31 and pins 30 to the turningpart of pipe I as disposed above the tumingjoint III.

A joint I l for turning on a horizontal axis connects pipe 1 to boompipe 2. That axis (36) is also the stationary pivot axis for the boom asa whole. Hydraulic actuators 28 and 29 pivot the heavy boom on thataxis. Of course, pipe 1 must be suspended near the top of tower 13, asclose as possible to upper turning joint 11 as provided between standpipe 1 and boom pipe 2, so that changes in length (due to temperaturevariations) remain without influence on the position of the pivot axis.

Boom pipe 2 is connected to descending end pipe 3 by means of anotherturning joint 12 (see FIG. 8) also turning on a horizontal axis. Pipe 2itself is actually supported by a boom system which is constructed ascantilever but has a rearward extension for weight balancing. The boomsystem includes girder structure L's-I6; particularly there is an uppergirder structure or beam 16 extending generally parallel to a lowergirder or beam 15. The cantilever ends of beams I5 and 16 areinterconnected by pivot linkage 18, while a pivot linkage l9interconnects the beams above the tower. Beams I5 and 16, and pivotlinkages I8 and 19 establish a carrier parallelogram, permittingparallel motion upon pivoting of the boom on the axis 36, which is thepivot axis of the boom on the tower. Upper girder system 16 is extendedto the rear beyond connection to the tower structure. The resultingextension arm 21 carries a balancing weight 22.

FIG. 6 shows two possibilities of supporting pipe 2 in the boom definingbeam or girder structure 15/16. Line 38 defines the separation plane forthe two cases. To the left of line 38 there is shown structure forsuspending pipe 2 in a pendulumlike fashion from upper beam structure16. The suspension is established by arms 25, pivotally linked to both,girder and pipe, to follow angle changes of the parallelogram. inreality, the structure is, of course, symmetrically duplicated to right.The second structure, as actually shown to the right of plane 38,illustrates pipe 2 as supported by lower girder 15, there being asupport element 33 permitting relative displacement, parallel to theextension of pipe 2, and between the latter and the beams 15.

A particular swing 24 supports pipe 2 close to the turning joint ll, torelieve the latter joint from the weight of pipe 2 and to secure theposition of the upper end of the stand pipe 1.

The descending end pipe 3 is supported in a suspended arm structure 17by means of a plurality of swinging support and suspension elements 27.The lower end of pipe 3 is linked to the lower end of arm structure 17by two parallely, positioned short arms 26, each pivotally linked toboth, suspended beam 17 and pipe 3. There are additional connectingelements 34 disposed on the pipe 3 for pivotal linking to cantileversuspension arms 27 that hold pipe 3.

FIG. 2 illustrates particular linkage between the free end of the boomstructure and the upper end of suspended arm or beam 17. FIG. 7 showssections through that structure and through pipe 3.

Insulation 35 isolates pipe 3 from the environment. In order to inhibitthermal conduction through the several elements 25, 27, 32 and 34, thatlink piping with support structure, may be made of material having lowthermal conductivity.

The section view B-B in FIG. 9 illustrates further details particularlyas they relate to the stationary axis 36 (horizontal) and the stationaryturning axis 37 (vertical). The axis 36 is actually defined by journalpins or bolts 20 connecting support tower 13 to the anchoring end oflower cantilever girder IS. The turning axis 37 of the boom, however, isdefined by the axis of turning joint l0 and by the slewing ring 14.

Another embodiment of the invention is shown in FIG. et seq. Thedelivery equipment has three pipes as conduits for fluids and forconnection to a pipeline. The basic conduits are plural stand pipes l,plural boom pipes 2, and plural suspended pipes 3'. The latter has itslower end also provided with connection means 4', for connection to theinlet and outlet of a tanker. Line 5 denotes the fluid flow path throughthe equipment.

Hoses 6' provides fluid conductive connection between the several pipes.However, some or all of these hoses may be replaced by turning joints orby articulated pipe joints or the like, see for example FIG. 13.

As in FIGS. 1 through 9, the stand pipes 1' are suspended from the topof a support tower 13; pins 30 permit swinging pendulum-like suspension.Also, tower I3 is biparted by slewing ring 14 to have a lower,stationary part and an upper, turning part. The pipes l are alsosuspended from the turning part. The pins 30, as extending from the pipeI, are received by sockets or bearings ports acting as drivers forfollower action, so that the pipes are turned together with the upperpart of tower 13. A hydraulic servo motor (not shown) drives thatturning part of the tower. The pin-receiver structure 30-31 takes up theweight of pipes 1'.

Each of the boom pipes 2', as connected respectively to descending pipes3, is supported by a balanced boom system. This system is comprised ofcantilever arm structure l5, l6, l8 and 19 as before establishing theparallelogram. There is also the balancing rearward extension 2!, 22.Extension 21 is variable for variable lever arm length; also, weight 22is variable.

A swinging-pendulum type bearing 24 for each boom pipe 2' in closeproximity to turning joint ll (FIG. 13) secures pipes l in theirrespective upper end position. Also, load relief is provided by thisconstruction. Each descending pipe 3' is suspended in arm 17 by meansdisplaceable, swinging suspension elements 27.

The lower ends of pipes 3 and of arm 17 are articulated. The three standpipes l are particularly shown side by side in FIG. 12, otherwise thisFigure corresponds to H6. 9 in principle, as far as support structure isconcerned.

The invention is not limited to the embodiments described above but allchanges and modifications thereof not constituting departures from thespirit and scope of the invention are intended to be included.

We claim:

1. Delivery system for loading and unloading of tankers using a cranetower and a boom supported in cantilever configuration by the tower forpivoting on the top of the tower, the cantilever having weight balancingextension; the improvement comprising:

a support arm pivotally suspended from the end of the boom arm andhaving girders carried by the boom arm;

first pipe means suspended from the top of the tower and disposed forrunning up in the tower;

second pipe means suspended from the girders of the boom arm andsupported by the boom arm in multiple spacedapart points along theextension of the arm including sup port points displaced from either endof the second pipe means; and

third pipe means supported in multiple, spaced-apart points in thesuspended arm;

the first, second and third pipe means fluid conductively interconnectedto obtain continuous, closed conduit means for fluid, there being aturning joint between first and second pipe means and a turning jointbetween the second and third joint means, only one thereof being securedto the boom arm for compensation of changes in length of the second pipemeans due to temperature variations.

2. Delivery system as in claim 1, the tower provided for turning theboom on a vertical axis and for pivoting the boom on a horizontal axis,boom and tower disposed for the second pipe to turn and to pivotrespectively on the same axes.

3. Delivery system as in claim 1, the first pipe means suspended fromthe top of the tower, and means on the first pipe means for compensationof length variations upon changes in temperature.

4. System as in claim 3, the first pipe means having first and secondsections, there being a turning joint interconnecting the first andsecond sections underneath suspension from the tower.

5. System as in claim 1, the boom comprised oftwo parallely, disposedgirders linked for parallel motion, there being an upper and a lowergirder, the lower one of the two girders pivotally linked to the tower,the free ends of the two girders linked by a pendulum suspension for andrigidly extending from the suspended arm, the upper one of the twogirders extended to the rear and carrying a balancing weight, the secondpipe disposed in the lower girder, there being means providing pendulumsuspension for the second pipe from the upper girder, acting on the pipein between the respective joints to the first and third pipe.

6. System as in claim 1, the second pipe positioned in the boom forsliding motion due to temperature variations, the joint to the firstpipe being stationary, the third pipe mounted to the suspended arm formotion relative to each other, there being pivot means provided for themounting.

7. System as in claim I, there being means for mounting the pipesrespectively to tower, boom and arm, the means, at least partially,having low thermal conductivity.

8. System as in claim 7, the first, second and third pipe means clad inthermal insulation.

9. System as in claim I, the pipe means each including at least twopipes running parallel to each other for establishing separate fluidpaths.

10. System as in claim 9, the first, second and third pipe means,respectively, comprised of first, second and third pluralities of pipes,the pipes of the second plurality disposed in a plane, and respectivelyjoined to the pipes of the third plurality disposed in a differentplane, the pipes of the first plurality I joined to the pipes of thesecond plurality permitting turning motion about the axis of the boom,the pipes of the first plurality as a whole about a vertical axis.

11. Systemwas in claim 9, the several pipes releasably disposed forindividual removal.

12. System as in claim 9, the balancing weight and the effective lengthof the extension being adjustable.

1. Delivery system for loading and unloading of tankers using a cranetower and a boom supported in cantilever configuration by the tower forpivoting on the top of the tower, the cantilever having weight balancingextension; the improvement comprising: a support arm pivotally suspendedfrom the end of the boom arm and having girders carried by the boom arm;first pipe means suspended from the top of the tower and disposed forrunning up in the tower; second pipe means suspended from the girders ofthe boom arm and supported by the boom arm in multiple spaced-apartpoints along the extension of the arm including support points displacedfrom either end of the second pipe means; and third pipe means supportedin multiple, spaced-apart points in the suspended arm; the first, secondand third pipe means fluid conductively interconnected to obtaincontinuous, closed conduit means for fluid, there being a turning jointbetween first and second pipe means and a turning joint between thesecond and third joint means, only one thereof being secured to the boomarm for compensation of changes in length of the second pipe means dueto temperature variations.
 2. Delivery system as in claim 1, the towerprovided for turning the boom on a vertical axis and for pivoting theboom on a horizontal axis, boom and tower disposed for the second pipeto turn and to pivot respectively on the same axes.
 3. Delivery systemas in claim 1, the first pipe means suspended from the top of the tower,and means on the first pipe means for compensation of length variationsupon changes in temperature.
 4. System as in claim 3, the first pipemeans having first and second sections, there being a turning jointinterconnecting the first and second sections underneath suspension fromthe tower.
 5. System as in claim 1, the boom comprised of two parallely,disposed girders linked for parallel motion, there being an upper and alower girder, the lower one of the two girders pivotally linked to thetower, the free ends of the two girders linked by a pendulum suspensionfor and rigidly extending from the suspended arm, the upper one of thetwo girders extended to the rear and carrying a balancing weight, thesecond pipe disposed in the lower girder, there being means providingpendulum suspension for the second pipe from the upper girder, acting onthe pipe in between the respective joints to the first and third pipe.6. System as in claim 1, the second pipe positioned in the boom forsliding motion due to temperature variations, the joint to the firstpipe being stationary, the third pipe mounted to the suspended arm formotion relative to each other, there being pivot means provided for themounting.
 7. System as in claim 1, there being means for mounting thepipes respectively to tower, boom and arm, the means, at leastpartially, having low thermal conductivity.
 8. System as in claim 7, thefirst, second and third pipe means clad in thermal insulation.
 9. Systemas in claim 1, the pipe means each including at least two pipes runningparallel to each other for establishing separate fluid paths.
 10. Systemas in claim 9, the first, second and third pipe means, respectively,comprised of first, second and third pluralities of pipes, the pipes ofthe second plurality disposed in a plane, and respectively joined to thepipes of the third plurality disposed in a different plane, the pipes ofthe first plurality joined to the pipes of the second pluralitypermitting turning motion about the axis of the boom, the pipes of thefirst plurality being suspended from the tower, and conduit means at thelower ends of the pipes of the first plurality for compensating positionchanges upon turning of the pipes of the first plurality as a wholeabout a vertical axis.
 11. System as in claim 9, the several pipesreleasably disposed for individual removal.
 12. System as in claim 9,the balancing weight and the effective length of the extension beingadjustable.